Department of Animal and Food Sciences, Texas Tech University, Box 42141, Lubbock 79409, USA.
J Anim Sci. 2011 Feb;89(2):549-59. doi: 10.2527/jas.2010-3049. Epub 2010 Oct 29.
Two studies were conducted to evaluate effects of wet distillers grains with solubles (WDG) and dietary concentration of alfalfa hay (AH) on performance of finishing beef cattle and in vitro fermentation. In both studies, 7 treatments were arranged in a 2 × 3 + 1 factorial; factors were dietary concentrations (DM basis) of WDG (15 or 30%) and AH (7.5, 10, or 12.5%) plus a non-WDG control diet that contained 10% AH. In Exp. 1, 224 beef steers were used in a randomized complete block (initial BW 342 kg ± 9.03) finishing trial. No WDG × AH interactions were observed (P > 0.12). There were no differences among treatments in final shrunk BW or ADG (P > 0.15), and DMI did not differ with WDG concentration for the overall feeding period (P = 0.38). Increasing dietary AH concentration tended (P < 0.079) to linearly increase DMI, and linearly decreased (P < 0.05) G:F and calculated dietary NE(m) and NE(g) concentrations. Carcasses from cattle fed 15% WDG had greater yield grades (P = 0.014), with tendencies for greater 12th-rib fat (P = 0.054) and marbling score (P = 0.053) than those from cattle fed 30% WDG. There were no differences among treatments (P > 0.15) in HCW, dressing percent, LM area, KPH, proportions of cattle grading USDA Choice, and incidence of liver abscesses. In Exp. 2, ruminal fluid was collected from 2 ruminally cannulated Jersey steers adapted to a 60% concentrate diet to evaluate in vitro gas production kinetics, H(2)S production, IVDMD, and VFA. Relative to the control substrate, including WDG in substrates increased (P < 0.01) H(2)S production and decreased total gas production (P = 0.01) and rate of gas production (P = 0.03). Increasing substrate WDG from 15 to 30% increased (P < 0.05) H(2)S production and decreased (P < 0.001) total gas production, with a tendency (P = 0.073) to decrease IVDMD and fractional rate of gas production (P = 0.063). Treatments did not significantly affect (P > 0.09) molar proportions or total concentration of VFA. Results indicate that including 15 or 30% WDG in steam-flaked corn-based diets did not result in major changes in feedlot performance or carcass characteristics, but increasing AH concentration from 7.5 to 12.5% in diets containing WDG decreased G:F. Including WDG in substrates decreased rate and extent of gas production and increased H(2)S production. Changes in various measures of in vitro fermentation associated with AH concentrations were not large.
进行了两项研究，以评估湿酒糟及其可溶性物（WDG）和饲粮中苜蓿干草（AH）浓度对育肥牛生产性能和体外发酵的影响。在两项研究中，均采用 2×3+1 因子设计，因子分别为 WDG（15 或 30%）和 AH（7.5、10 或 12.5%）的饲粮浓度（DM 基础）和不含 WDG 的对照饲粮，该对照饲粮含有 10%的 AH。在试验 1 中，224 头肉牛随机分成完全区组（初始 BW 342kg±9.03kg）进行育肥试验。WDG×AH 无互作（P＞0.12）。各处理组间终末缩躯重或 ADG 无差异（P＞0.15），整个饲养期内 DMI 不受 WDG 浓度影响（P=0.38）。饲粮中 AH 浓度增加，DMI 呈趋势性增加（P＜0.079），而 G:F 和计算的饲粮 NE(m)和 NE(g)浓度呈线性下降（P＜0.05）。饲喂 15% WDG 的牛的胴体产肉等级更高（P=0.014），12 肋脂肪（P=0.054）和大理石花纹评分（P=0.053）呈线性增加，高于饲喂 30% WDG 的牛。各处理组间（P＞0.15）HCW、胴体率、LM 面积、KPH、美国农业部选择分级比例和肝脓肿发生率无差异。在试验 2 中，从 2 头适应 60%精料饲粮的瘤胃瘘管泽西奶牛中收集瘤胃液，以评估体外产气量动力学、H2S 产生、IVDMD 和 VFA。与对照底物相比，包含 WDG 的底物增加了（P＜0.01）H2S 产生，并降低了总产气量（P=0.01）和产气量速率（P=0.03）。底物中 WDG 从 15%增加到 30%，增加了（P＜0.05）H2S 产生，降低了（P＜0.001）总产气量，产气量速率呈下降趋势（P=0.073）（P=0.063）。处理组对 VFA 的摩尔比例或总浓度没有显著影响（P＞0.09）。结果表明，在蒸汽压片玉米基础饲粮中添加 15%或 30%的 WDG 不会显著改变肥育牛的生产性能或胴体特性，但饲粮中 AH 浓度从 7.5%增加到 12.5%，降低了 G:F。底物中添加 WDG 降低了产气量的速率和程度，增加了 H2S 的产生。与 AH 浓度相关的各种体外发酵指标的变化不大。
